| Registro completo |
| Provedor de dados: |
PAB
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| País: |
Brazil
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| Título: |
Mutants of common bean alpha-amylase inhibitor-2 as an approach to investigate binding specificity to alpha-amylases
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| Autores: |
Silva,Maria Cristina Mattar da
Mello,Luciane Vieira
Coutinho,Marise Ventura
Rigden,Daniel John
Neshich,Goran
Chrispeels,Maarten John
Grossi-de-Sá,Maria Fátima
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| Data: |
2004-03-01
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| Ano: |
2004
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| Palavras-chave: |
Phaseolus vulgaris
A-amylase inhibitors
Inhibitor specificity
Site directed mutagenesis
Structural modeling
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| Resumo: |
Despite the presence of a family of defense proteins, Phaseolus vulgaris can be attacked by bruchid insects resulting in serious damage to stored grains. The two distinct active forms of a-amylase inhibitors, a-AI1 and a-AI2, in P. vulgaris show different specificity toward a-amylases. Zabrotes subfasciatus a-amylase is inhibited by a-AI2 but not by a-AI1. In contrast, porcine a-amylase is inhibited by a-AI1 but not by a-AI2. The objective of this work was to understand the molecular basis of the specificity of two inhibitors in P. vulgaris (a-AI1 and a-AI2) in relation to a-amylases. Mutants of a-AI2 were made and expressed in tobacco plants. The results showed that all the a-AI2 mutant inhibitors lost their activity against the insect a-amylases but none exhibited activity toward the mammalian a-amylase. The replacement of His33 of a-AI2 with the a-AI1-like sequence Ser-Tyr-Asn abolished inhibition of Z. subfasciatus a-amylase. From structural modeling, the conclusion is that the size and complexity of the amylase-inhibitor interface explain why mutation of the N-terminal loop and resultant abolition of Z. subfasciatus a-amylase inhibition are not accompanied by gain of inhibitory activity against porcine a-amylase.
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| Tipo: |
Info:eu-repo/semantics/article
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| Idioma: |
Inglês
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| Identificador: |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2004000300001
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| Editor: |
Embrapa Secretaria de Pesquisa e Desenvolvimento
Pesquisa Agropecuária Brasileira
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| Relação: |
10.1590/S0100-204X2004000300001
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| Formato: |
text/html
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| Fonte: |
Pesquisa Agropecuária Brasileira v.39 n.3 2004
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| Direitos: |
info:eu-repo/semantics/openAccess
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